Structural studies of the system trans-stilbene/trans-azobenzene. III. The structures of three mixed crystals of trans-azobenzene/trans-stilbene; determinations by X-ray and neutron diffraction

Abstract

Abstract. (C 14 HI2) 71069A; no structure determination. The mixed crystals not only exhibit substitutional disorder but both molecules, trans-azobenzene and trans-stilbene, also show configurational disorder at one of the two independent sites with symmetry 1. The structure refinements, in which both kinds of disorder were taken into account, were performed with constraints and restraints. The trans-stilbene molecules show a slight preference for substitution at the disordered sites. This preference can be understood by geometrical considerations.

Synthesis, Structure, and Reactivity of Diazene Adducts: Isolation of iso‐Diazene Stabilized as a Borane Adduct

“…Compound 5 (Figure 3 top) crystallizes in the monoclinic space group P2 1 /c with eight formula units per cell. For the two independent molecules the same positional disorder was observed as discussed for trans-PhÀN=NÀPh [95] and 2. [37] The observed molecular structure exhibits the expected trans configuration (Si-N-N-C = 179.78) with a short N-N distance (1.238(2) ; cf.…”

“…Because the structures of trans-PhÀN=NÀPh [94,95] and 2 [37] have been reported before, we focus the following discussion on 5. Compound 5 (Figure 3 top) crystallizes in the monoclinic space group P2 1 /c with eight formula units per cell.…”

1:1 Complexes of octafluoronaphthalene with trans-stilbene and trans-azobenzene

“…It is well known that the crystals of pure tolan [21] are isostructural with those of (E)-or trans-stilbene [22] and trans-azobenzene [23]. Furthermore, the two latter compounds are isomorphous in the strict sense, forming a series of solid solutions (mixed crystals), several of which have been characterised by full single-crystal X-ray diffraction studies [24]. Therefore, we undertook to investigate whether this structural similarity would extend to the corresponding complexes with OFN.…”

Structural peculiarities of configurational isomers of 1‐styrylpyrroles according to 1Н, 13С and 15N NMR spectroscopy and density functional theory calculations: electronic and steric hindrance for planar structure

“…Influence of the competitive conjugation on the molecule planarity is indirectly confirmed by the data of crystallographic studies of the substituted trans ‐stilbenes. For parent trans ‐stilbene, the crystallographic study shows relatively small deviation of the phenyl rings from the plane of the double bond (corresponding dihedral angles ψ 1 and ψ 2 is 4 and 9°, Scheme ) . However, in the presence of donor substituents in the para or meta positions of the phenyl rings (R = NH 2 , OH, OCH 3 , Scheme ), dihedral angles ψ 1 and ψ 2 increase to 23–30 probably because of oppositely directed donor π–π conjugations.…”